The present invention relates generally to shut down of propulsion engines of marine vessels during seaway travel.
Devices for plugging of tubular pipes to block flow of fluids therethrough, are generally well known. It is also well known in the art, that build up of exhaust back pressure to certain high levels in fuel burning combustion engines, will cause engine shut down. It is an important object of the present invention to produce such engine shut down without engine damage under high temperature and full engine speed conditions by exhaust gas flow blockage to cause sufficient back-up pressure build-up.
In accordance with the present invention, engine shut down by build up of exhaust back-up pressure is effected by insertion of a flow blocking device into an engine exhaust stack during outflow of the exhaust gas therefrom under full engine speed. Pursuant to certain embodiments of the invention, such flow blocking device is inserted by cable lowering from a helicopter into the exhaust stack associated with the fuel burning propulsion engine of a marine vessel undergoing seaway travel at full engine speed. Entry of the flow blocking device into the exhaust stack stops outflow of the exhaust gas to cause back pressure build-up therein. The requisite duration for such flow blocking action is insured according to one embodiment by mechanical means after entry of the flow blocking device, to prevent its ejection from the stack by the back pressure build-up therein. Also, according to other embodiments a sequence of events is initiated after the flow blocking device reaches a lowermost position within the exhaust stack to perform the flow blocking function. Such events may include water cooling of the exhaust gas to low temperature conditions within the exhaust stack under which a flexible portion of the flow blocking device is inflated or expanded into contact with the stack for pressurized sealing there to block exhaust outflow until engine shut down occurs.